A number of local acquaintances are reporting their flashes, regardless of manufacturer, are, for want of a better term, blowing up. While there could be a number of reasons for this, the one thing in common is shooting in very cold, -20C to -35C weather. In researching this I couldn't find much in the way of cold weather flash work other than the usual let your equipment slowly warm up when coming indoors.
It would seem to me that while the duration of a flash is short, the heat given off, with repeated cold weather use, may damage the flash. Would be interested in anybody's experience in this regard.